3 # Script helping make fast-forwarding histories while still rebasing
4 # upstream deltas when working on Debian packaging
6 # Copyright (C)2017 Ian Jackson
8 # This program is free software: you can redistribute it and/or modify
9 # it under the terms of the GNU General Public License as published by
10 # the Free Software Foundation, either version 3 of the License, or
11 # (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program. If not, see <http://www.gnu.org/licenses/>.
22 # git-debrebase status
23 # git-debrebase start # like ffqrebase start + debrebase launder
24 # git-debrebase new-upstream [stuff] # see below
25 # git-debrebase <git-rebase options> # does debrebase start if necessary
27 # git-debrebase analyse
28 # git-debrebase launder # prints breakwater tip
29 # git-debrebase create-new-upstream-breakwater [-f] <upstreaminfo>...
32 # [,][<subdir>:][+]<commitid>[,...]
34 # if initial comma is supplied, entries are not positional. Unspecified
35 # <subdir> means root (and there may be only one).
36 # xxx want auto branch names
39 # [+]<commit> [<subdir/> [+]<commit>...]
41 # --new-upstream-different-subtrees
44 # git-debrebase new-upstream
45 # - previous breakwater merge must be gdr-generated
46 # - orig set is the same as before
47 # - implicitly uses upstream branches according to orig set
48 # - not all upstream branches need be updated
49 # - insists on fast-forward of each branch, unless
50 # --force (or --force=<subdir>[/])
51 # branch set adjustments
52 # git-debrebase new-upstream --add <subdir>/
53 # git-debrebase new-upstream --rm <subdir>/
54 # git-debrebase new-upstream / [<subdir>/ ...]
55 # - orig set is adjusted
56 # - otherwise like auto (--add is not checked for ffness, obv)
57 # - multiple --add and --rm may be specified
58 # - --add makes new upstream the last contributor
60 # git-debrebase / [<rootcommitid>] [<subdir>/ [<commitid>] ...]
61 # - orig set is precisely as specified now
62 # - previous breakwater merge is irrelevant
63 # - no fast forward checks
64 # for now only explicit with commitids
66 # implicitly uses `upstream'
67 # # (or multiple other branches)
68 # git-debrebase new-upstream \
69 # [<subdir>/]=<commitid>
71 # UPSTREAM[,[[SUBDIR:]SUBUPSTREAM]
72 # default for SUBDIR: is from previous upstream merge[xxx terminology]
76 # when starting must record original start (for ff)
77 # and new rebase basis
79 # git-ffqrebase start [BASE]
80 # # records previous HEAD so it can be overwritten
81 # # records base for future git-ffqrebase
82 # git-ffqrebase set-base BASE
83 # git-ffqrebase <git-rebase options>
84 # git-ffqrebase finish
85 # git-ffqrebase status [BRANCH]
87 # refs/ffqrebase-prev/BRANCH BRANCH may be refs/...; if not it means
88 # refs/ffqrebase-base/BRANCH refs/heads/BRANCH
89 # zero, one, or both of these may exist
96 use Debian::Dgit qw(:DEFAULT $wa);
101 my @cmd = qw(git config -z);
102 push @cmd, qw(--get-all) if wantarray;
104 my $out = cmdoutput @cmd;
105 return split /\0/, $out;
112 my ($type,$data) = git_cat_file $objid;
113 die unless $type eq 'commit';
114 $data =~ m/(?<=\n)\n/;
118 sub D_DEB () { return 0x1; }
119 sub D_UPS () { return 0x2; }
120 sub D_PAT_ADD () { return 0x4; }
121 sub D_PAT_OTH () { return 0x8; }
123 our $rd = ".git/git-debrebase";
124 our $ud = "$rd/work";
126 sub commit_pr_info ($) {
128 return Data::Dumper->dump([$r], [qw(commit)]);
131 sub calculate_committer_authline () {
132 my $c = cmdoutput @git, qw(commit-tree --no-gpg-sign -m),
133 'XXX DUMMY COMMIT (git-debrebase)', "$basis:";
134 my ($h,$m) = get_commit $c;
135 $h =~ m/^committer .*$/m or confess "($h) ?";
142 my ($h,$m) = get_commit $objid;
144 my ($t) = $h =~ m/^tree (\w+)$/m or die $cur;
145 my (@ph) = $h =~ m/^parent (\w+)$/m;
156 foreach my $ph (@ph) {
160 Differs => (get_differs $t, $ph),
165 my ($type, @rest) = @_;
166 $r = { %r, Type => $type, @rest };
171 $r = { %r, Type => Unknown };
176 my $d = $r->{Parents}[0]{Differs};
177 if ($d == D_DPAT_ADD) {
178 return $classify->(qw(AddPatches));
179 } elsif ($d & (D_DPAT_ADD|D_DPAT_OTH)) {
180 return $unknown->("edits debian/patches");
181 } elsif ($d == D_DEB) {
182 return $classify->(qw(Packaging));
183 } elsif ($d == D_UPS) {
184 return $classify->(qw(Upstream));
185 } elsif ($d == D_DEB|D_UPS) {
186 return $classify->(qw(Mixed));
188 return $unknown->("no changes");
190 confess "internal error $objid ?";
194 return $unknown->("origin commit");
197 my @identical = grep { !$_->{Differs} } @p;
198 if (@p == 2 && @identical == 1) {
199 my @overwritten = grep { $_->{Differs} } @p;
200 confess "internal error $objid ?" unless @overwritten==1;
201 return $classify->(qw(Pseudomerge),
202 Overwritten => $overwritten[0],
203 Contributor => $identical[0]);
205 if (@p == 2 && @identical == 2) {
206 my @bytime = nsort_by {
207 my ($ph,$pm) = get_commit $_->{CommitId};
208 $ph =~ m/^committer .* (\d+) [-+]\d+$/m or die "$_->{CommitId} ?";
211 return $classify->(qw(Pseudomerge),
212 SubType => qw(Ambiguous),
213 Overwritten => $bytime[0],
214 Contributor => $bytime[1]);
217 my ($p_h, $p_m) = get_commit $p;
218 $p->{IsOrigin} = $p_h !~ m/^parent \w+$/m;
219 ($p->{IsDgitImport},) = $p_m =~ m/^\[dgit import ([0-9a-z]+) .*\]$/m;
221 my @orig_ps = grep { ($_->{IsDgitImport}//'X') eq 'orig' };
223 if (!(grep { !$_->{IsOrigin} } @p) and
224 (@origs >= @p - 1) and
225 $m2 =~ s{^\[(dgit import unpatched .*)\]$}{[was: $1]}m) {
227 return $classify->(qw(DgitImportUnpatched),
228 OrigParents => \@orig_ps);
231 my ($stype, $series) = git_cat_file "$t:debian/patches/series";
232 my $haspatches = $stype ne 'missing' && $series =~ m/^\s*[^#\n\t ]/m;
234 # How to decide about l/r ordering of breakwater merges ? git
235 # --topo-order prefers to expand 2nd parent first. There's
236 # already an easy rune to look for debian/ history anyway (git log
237 # debian/) so debian breakwater branch should be 1st parent; that
238 # way also there's also an easy rune to look for the upstream
239 # patches (--topo-order).
242 !$p[0]{IsOrigin} && # breakwater merge never starts with an origin
243 !($p[0]{Differs} & ~D_DEB) &&
244 !($p[1]{Differs} & ~D_UPS)) {
245 return $classify->(qw(BreakwaterUpstreamMerge),
249 return $unknown->("complex merge");
253 my ($input, $pseudos_must_overwrite_this, $wantdebonly) = @_;
254 # go through commits backwards
255 # we generate two lists of commits to apply
256 my (@deb_cl, @ups_cl, @processed);
262 my ($appendinfo) = @_;
265 $ms .= "\n\n[git-debrebase $appendinfo]\n";
268 my $rewrite_from_here = sub {
269 push @processed, { SpecialMethod => 'StartRewrite' };
276 my $ty = $cl->{Type};
277 my $st = $cl->{SubType};
278 $found{$ty. ( defined($st) ? "-$st" : '' )}++;
279 my $p0 = $cl->{Parents}[0]{CommitId};
280 if ($ty eq 'AddPatches') {
282 $rewrite_from_here->();
284 } elsif ($ty eq 'Packaging') {
286 push @processed, $cl;
289 } elsif ($ty eq 'Upstream') {
291 push @processed, $cl;
294 } elsif ($ty eq 'Mixed') {
297 my $cls = { $cl, $xmsg->("split mixed commit: $wh part") };
300 $queue->(\@deb_cl, "debian");
301 $queue->(\@ups_cl, "upstream");
302 $rewrite_from_here->();
304 } elsif ($ty eq 'Pseudomerge') {
305 if (defined $pseudos_must_overwrite_this) {
306 confess 'xxx actually check this';
308 push @pseudomerges, $cl;
309 $rewrite_from_here->();
310 $cur = $ty->{Contributor};
312 } elsif ($ty eq 'BreakwaterUpstreamMerge') {
315 } elsif ($ty eq 'DgitImportUnpatched' &&
316 @pseudomerges == 1) {
317 # This import has a tree which is just like a breakwater
318 # tree, but it has the wrong history. Its ought to have
319 # the previous breakwater (which dgit ought to have
320 # generated a pseudomerge to overwrite) as an ancestor.
321 # That will make the history of the debian/ files correct.
322 # As for the upstream version: either it's the same upstream
323 # as the previous breakwater, in which case that history is
324 # precisely right. Otherwise, it was a non-gitish upload
325 # of a new upstream version. We can tell these apart
326 # by looking at the tree of the supposed upstream.
327 if ($differs & D_UPS) {
330 SpecialMethod => 'DgitImportUpstreamUpdate',
331 $xmsg->("convert dgit import: debian changes")
336 SpecialMethod => 'DgitImportDebianUpdate',
337 $xmsg->("convert dgit import: upstream changes")
339 my $differs = get_differs $previous_breakwater, $cl->{Tree};
340 $basis = launder $pseudomerges[0]{Overwritten}, undef, 1;
341 $rewrite_from_here->();
344 die "Reached difficult commit $cur: ".Dumper($cl);
347 # Now we build it back up again
350 in_workarea sub { xxx attributes xxx };
356 my $rm_tree_cached = sub {
358 runcmd @git, qw(rm --quiet -rf --cached), $subdir;
360 my $read_tree_debian = sub {
362 $rm_tree_cached->(qw(debian));
363 runcmd @git, qw(read-tree --prefix=debian/), "$treeish:debian";
365 my $read_tree_upstream = sub {
367 runcmd @git, qw(read-tree), $treeish;
368 $read_tree_debian->($build);
371 my $committer_authline = calculate_committer_authline();
374 mkdir $rd or $!==EEXIST or die $!;
376 foreach my $cl (qw(Debian), (reverse @deb_cl),
377 { SpecialMethod => 'RecordBreakwaterTip' },
378 qw(Upstream), (reverse @ups_cl)) {
380 $current_method = $cl;
383 $method = $cl->{SpecialMethod} // $current_method;
384 my @parents = ($build);
385 my $cltree = $cl->{CommitId}
386 if ($method eq 'Debian') {
387 $read_tree_debian->($cltree);
388 } elsif ($method eq 'Upstream') {
389 $read_tree_upstream->($cltree);
390 } elsif ($method eq 'StartRewrite') {
393 } elsif ($method eq 'RecordBreakwaterTip') {
394 last if $wantdebonly;
395 $breakwater = $build;
397 } elsif ($method eq 'DgitImportDebianUpdate') {
398 $read_tree_debian->($cltree);
399 $rm_tree_cached(qw(debian/patches));
400 } elsif ($method eq 'DgitImportUpstreamUpdate') {
401 $read_tree_upstream->($cltree);
402 push @parents, map { $_->{CommitId} } @{ $cl->{OrigParents} };
406 $rewriting ||= $cl ne pop @processed;
407 my $newtree = cmdoutput @git, qw(write-tree);
409 $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
410 $ch =~ s{^parent .*\n}{}m;
411 $ch =~ s{(?=^author}{
412 map { "parent $_\n" } @parents
413 }me or confess "$ch ?";
415 $ch =~ s{^committer .*$}{$committer_authline}m
418 my $cf = "$rd/m$rewrite"
419 open CD, ">", $cf or die $!;
420 print CD $ch, "\n", $cl->{Msg}; or die $!;
422 my @cmd = (@git, qw(hash-object));
423 push @cmd, qw(-w) if $rewrite;
424 push @cmd, qw(-t commit), $cf;
425 my $newcommit = cmdoutput @cmd;
426 confess "$ch ?" unless $rewrite or $newcommit eq $cl->{CommitId};
431 runcmd @git, qw(diff-tree --quiet),
432 map { $wantdebonly ? "$_:debian" : $_ },
435 return ($build, $breakwater);
438 sub get_head () { return git_rev_parse qw(HEAD); }
440 sub update_head ($$) {
441 my ($old, $new, $mrest) = @_;
442 runcmd @git, qw(update-ref -m), "git-debrebase $mrest", $new, $old;
446 my $old = get_head();
447 my ($tip,$breakwater) = launder $old, 0, undef, 0;
448 update_head $old, $tip, 'launder'; # no tree changes! xxx debian/patches
449 printf "# breakwater tip:\n%s\n", $breakwater;
452 my $toplevel = runcmd @git, qw(rev-parse --show-toplevel);
453 chdir $toplevel or die "chdir $toplevel: $!";
455 my $cmd = shift @ARGV;
458 $cmdfn = ${*::}{"cmd_$cmdfn"};
460 $cmdfn or badusage "unknown git-debrebase sub-operation $cmd";